The present disclosure relates to a battery in which iron sulfide is used for the cathode and lithium (Li) metal or a lithium alloy is used for the anode.
Various batteries using lithium metal for the anode have been heretofore developed. One thereof is a lithium iron sulfide battery using iron sulfide for the cathode (for example, see Japanese Patent No. 3060109). The lithium iron sulfide battery is compatible with alkaline batteries, and thus the lithium iron sulfide battery is expected to be widely used. In addition, an AAA lithium iron sulfide battery has an average discharging voltage of about 0.2 V higher than that of the alkaline battery, and thus the AAA lithium iron sulfide battery has superior long-lasting use of about 15% over that of the alkaline battery in the case of constant output discharge. Further, the lithium iron sulfide battery has a spirally winding structure in which the cathode and the anode are layered and spirally wound unlike the alkaline battery. Therefore, the lithium iron sulfide battery has superior heavy load discharge characteristics. For example, when the lithium iron sulfide battery is used for a digital camera, it is possible to increase number of shots by more than double that of the alkaline battery.
However, the capacity of the lithium iron sulfide battery is slightly inferior to that of the alkaline battery. Therefore, for example, in the case of light load discharge in a headphone stereo set or the like, it is difficult for the lithium iron sulfide battery to gain superiority to the alkaline battery. It is considered that by increasing the electrode thickness, the amount of active material filled in the battery is increased to improve the capacity. However, when the electrode thickness is increased, the heavy load characteristics are lowered.
In view of the foregoing, it is desirable to provide a battery capable of improving the discharge capacity while maintaining the high load characteristics.